Molecular fragment statistics from compounds tested in the prescreen, P388 leukemia, have been used to create programs that provide estimates of anti-tumor activity and novelty. For the past five years, these estimates have aided the medicinal chemist in selecting compounds for screening. In selecting our current input of 10,000 compounds per year, two to three times that many potential acquisitions are run through the programs. Refinements and extensions are continuously being introduced. This year data from L1210 leukemia and B16 melanoma were combined with P388 into an aggregate antitumor model. Also, a large-scale literature surveillance project was undertaken by running several hundred thousand compounds through the antitumor activity and novelty programs. These compounds were registered by Chemical Abstracts Service (CAS) before 1978 when DTP began its own literature searches. In contrast to the acquisition stream, where every structure is considered, only the top 5% according to an optimized activity and novelty criterion are examined as candidates to be requested for acquisition. This year also wrought the conversion from CAS to DCRT as part of the new Drug Information System. This change as accompanied by a switch from the atom-centered fragments used in the Inquiry system to the more efficiently generated bond-centered fragments originally designed for literature surveillance. As an experiment in combining physical parameters with structure features, the whole set of data was separated according to disjoint ranges of log P, the octanol/water partition coefficient.